Preparation of Ultra Low- k Porous SiOCH Films from Ring-Type Siloxane with Unsaturated Hydrocarbon Side Chains by Spin-On Deposition

An ultra-low-dielectric-constant （ultra low-k, or ULK） porous SiOCH film is prepared using a single ring-type siloxane precursor of the 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane by means of spin-on deposition, followed by crosslinking reactions between the precursor monomers under UV irradiation. The as-prepared film has an ultra low k of 2.41 at 1 MHz due to incorporation of pores and hydrocarbon crosslinkages, a leakage current density of 9.86×10-7 A/cm2 at 1 MV/cm, as well as a breakdown field strength of ~1.5 MV/cm. Further, annealing at 300°C results in lower k （i.e., 1.94 at 1 MHz）, smaller leakage current density （2.96×10-7 A/cm2 at 1 MV/cm） and higher breakdown field strength （about 3.5 MV/cm）, which are likely caused by the short-ranged structural rearrangement and reduction of defects in the film. Finally, the mechanical properties and surface morphology of films are also evaluated after different temperature annealing.     

生物分子辅助的纳米材料绿色合成

纳米材料绿色合成的标准是合成需使用对环境无污染的溶剂体系、还原剂以及无毒的稳定剂来进行.生物分子具备有机和无机质导向生成的能力,且具有热和化学稳定性、容易获得、价格便宜,最重要的是对环境无污染,可用于纳米材料的绿色制备.本文就笔者在生物分子辅助绿色合成纳米材料方面的研究成果做一汇总和介绍.     

EFFECT OF WATER ON THE CONDUCTIVITY OF PPQ (ClO_4~-) COMPLEX

The preparation of conducting PPQ film was first reported in the previous paper. It is very interesting that this film is highly sensitive to moisture in air. The hydration and dehydration of the film are accompanied by change not only in color but also in conductivity and UV-visible spectrum. The conducting PPQ is reduced to PPQ and loses its conductivity after being soaked in water.     

几种芳杂环高分子膜对气体分离性能的研究

聚苯基-1,2,4-三嗪(PPT)、聚苯基单醚喹嗯啉(PPQ(E))、聚苯基喹哑心啉(PPQ(B))、聚酰亚胺(PI)和聚苯并咪唑吡咯酮(PY)均是耐高温高分子。本文制备了这些高聚物的均质膜(除PI外),研完了它们对O_2、N_2和H_2、N_2、CO、CH_4的分离性。